Abstract
The chromium pollution of water is an important environmental and health issue. Cr(VI) removal by means of metallic iron is an attractive method. Specifically, nanoscopic zero valent iron (NZVI) shows great reactivity, however, its applicability needs to be further investigated. In the present paper, NZVI was supported on MgO grains to facilitate the treatments for remediation of chromium-contaminated waters. The performances and mechanisms of the developed composite, in the removal of hexavalent chromium, were investigated by means of batch and continuous tests. Kinetic studies, under different operating conditions, showed that reduction of Cr(VI) could be expressed by a pseudo second-order reaction kinetic. The reaction rate increased with the square of Fe(0) amount, while it was inversely proportional to the initial chromium concentration. The process performance was satisfactory also under uncontrolled pH, and a limited influence of temperature was observed. The reactive material was efficiently reusable for many cycles without any regeneration treatment. The performances in continuous tests were close to 97% for about 80 pore volume of reactive material.
Highlights
Chromium is widely detected in surface water and groundwater because of its widespread application in metallurgy, organic chemical synthesis, leather tanning and wood preserving industries [1]
The Magnesium oxide (MgO) grains used in this study had a diameter ranging between 0.6 and 2 mm (Figure 1a)
As can be noticed by the observation of SEM (Scanning Electron microscopy) images (Figure 3b), the zones characterized by the presence of iron particles are well distributed on the grains of MgO-nanoscopic zero valent iron (NZVI)
Summary
Chromium is widely detected in surface water and groundwater because of its widespread application in metallurgy, organic chemical synthesis, leather tanning and wood preserving industries [1]. Chromium exists mainly in two oxidation states, Cr(VI) and Cr(III). Cr(III) is relatively nontoxic and has low solubility at a wide pH range [2,3]. It does not readily migrate in groundwater since it usually precipitates as hydroxides, oxides or oxyhydroxides [1]. In the treatment of drinking waters and wastewaters, conventional techniques, including precipitation, phytoextraction, reverse osmosis, electrodialysis, ion exchange, membrane filtration and adsorption, have been tested and developed [4]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
